1. Field of the Invention
The present invention relates generally to heat exchangers and, for example, to tubular heat exchangers forming condensers which are cleaned continuously by solid members systematically circulated for this purpose in one of the flows. The solid members may in practice be foam rubber balls.
2. Description of the Prior Art
The principle of the corresponding arrangements has long been known in the art, in particular from the documents U.S. Pat. No. 1,795,348 and DE-A-23 14 329.
The present invention is more particularly concerned with management of the solid cleaning members used in this way.
If arrangements of the kind described in the document FR-A-2 716 530 are used, for example, controlling the solid cleaning members entails, fundamentally, on the one hand, in order to prevent the solid cleaning members in question being evacuated to a drain with the flow that conveys them, the interposition, on the exit pipe of the heat exchanger, of interception element adapted to retain them, and, on the other hand, recycling, to the inlet pipe of the heat exchanger, solid cleaning members retained in this way by the interception element.
However, in practice, it is also necessary to pass the solid cleaning member systematically through a control device adapted in particular to control their number, to separate and eliminate those whose dimensions have, through wear, become smaller than required, and consequently to replenish the system with new solid cleaning members.
To operate correctly, the control device must have a flow with a given flowrate passing through it.
There has been proposed a control installation for solid cleaning members circulating in a heat exchanger to clean it, of the kind including interception element which, adapted to retain the circulating solid cleaning members, are interposed on the outlet pipe of the heat exchanger, a return pipe, which recycles toward the inlet pipe of the heat exchanger a return flow containing the solid cleaning members retained by the interception element, and, disposed on that return pipe, a control device for the solid cleaning members, in which installation, between the interception element and the control device, there is interposed, on the return pipe, a concentration device dividing the corresponding return flow into two parts; namely, a first part, or principal part, which normally contains all of the solid cleaning members, and which is directed toward the control device, and a second part, or diverted part, which normally contains no solid cleaning members, and which is separated from the control device, the return pipe forming part of circulation means which are adapted to generate, locally, via the interception element, a counter-current flow.
An installation of the above kind is described in the document FR-A-2 766 915, for example.
In this way, the control device is spared some of the flowrate of the return flow concerned, whilst normally receiving all of the solid cleaning element to be controlled.
To be more precise, for a given installation, the concentration device advantageously and systematically recreates at the inlet of the control device particular flow conditions which correspond to its normal operating conditions.
Accordingly, a standard control device can advantageously be used, regardless of the capacity of the installation to be treated, which is beneficial from the cost point of view.
Generally speaking, recycling solid cleaning members retained by the interception element to the inlet pipe of the heat exchanger is achieved by circulation means which push or drive the solid cleaning members toward said inlet pipe. This driving operation is necessarily effected via the interception element and leads to a costly and relatively complicated installation.
To avoid this drawback, the present invention provides a control installation for solid cleaning members circulating in a heat exchanger to clean it, of the kind including interception element which, adapted to retain the circulating solid cleaning members, are interposed on the outlet pipe of the heat exchanger, a return pipe, which recycles toward the inlet pipe of the heat exchanger a return flow containing the solid cleaning members retained by the interception element, and, disposed on that return pipe, a control device for the solid cleaning members, in which installation, between the interception element and the control device, there is interposed, on the return pipe, a concentration device dividing the corresponding return flow into two parts; namely, a first part, or principal part, which normally contains all of the solid cleaning members, and which is directed toward the control device, and a second part, or diverted part, which normally contains no solid cleaning members, and which is separated from the control device, the return pipe forming part of circulation means which are adapted to generate, locally, via the interception element, a counter-current flow, characterized in that the circulation means include suction means adapted to take up, to recycle them, in line with the interception element, the solid cleaning members retained thereby, the concentration device being of generally cylindrical shape and including a grid mounted to pivot about an axis in its central part so that it can occupy at least two extreme positions; namely, a position referred to as a xe2x80x9ccleaningxe2x80x9d position in which it allows free passage of the principal part of the return flow and is interposed in the passage of the diverted part of said flow, and a position referred to as a xe2x80x9cnon-cleaningxe2x80x9d position in which it is interposed in the passage of the principal part and the diverted part of the return flow.
The circulation means advantageously include a flow pipe established between the outlet pipe of the heat exchanger and its inlet pipe and connected to the suction of a pump which discharges into the concentration device.
The control installation preferably includes a recycling pipe which directs the diverted part of the return flow to the outlet pipe of the heat exchanger. The recycling pipe is connected to the flow pipe via the concentration device.
Concentration devices with tilting grids have already been proposed. To be more precise, there is known in the art a concentration device in which two grids disposed in a V-shape are mounted to pivot about an axis in their central part and can occupy at least two positions in a V-shape, the point of the V-shape being at the bottom in one of those positions and at the top in the other one. A concentration device of the above kind has the disadvantage that cleaning members are lost during the operation of recovering said members.
According to the invention, the concentration device is connected to the recycling pipe via a filter. This avoids losing any cleaning member.
The filter advantageously has a tubular wall which passes axially and in a sealed manner through an enclosure. The part of the tubular wall situated inside the enclosure being perforated. The tubular wall of the filter communicates with the concentration device via a valve.
The tubular wall of the filter preferably communicates with the outside via a valve.
The recycling pipe is advantageously connected to the outside wall of the enclosure. The recycling pipe is adapted to be shut off by a valve in line with its connection to the outside wall of the enclosure.
The upper part of the enclosure is preferably provided with a vent which is adapted to be shut off.